HTML Tags Allowed in Feature Description Popup

Hi,

Are IFRAME elements allowed to be inserted in the feature description popups?

Right now I have tried inserting the following iframe tag/content into the long feature description but in the silverlight 2.2 viewer only the tag markup is displayed - no active HTML content.

<iframe width="620" height="500" src="http://files.hazardhunter.com/geodata/vizzgits/templates/ge_balloon/ge_balloon_remote.html#view1" frameborder="0" allowfullscreen></iframe>

Am I making some rookie mistake here?

Also - Is there a list/more detailed description of HTML markup allowed insite the feature description and map tips popups?  In the documentation and examples Ive only seen reference (and examples) to images and hyperlinks.

Thanks